The invention relates to a protective device for a working member, such as the piston rod of a piston and cylinder actuator, which is arranged at least partly in a receiving member and is able to be moved and more especially slid, along a curved or straight path so that it projects to a greater or lesser extent out of the receiving member.
A large number of devices of this sort have been proposed in the past, which have a working member slidingly mounted in a receiving member so as to be able to moved in translation by operation of the device and to project to a lesser or greater extent out of the receiving member.
Such devices are for instance piston and cylinder actuators, whose piston running in the cylinder is connected with a piston rod extending to the outside and is provided with a means for connecting it with a load. Also devices with a sliding sleeve such as the tailstock of a lathe, are designed in this manner and comprise a cylindrical part sliding in a housing and which is caused to move to a greater or lesser extent out of the housing by a lead screw or by a fluid operated device. All these forms of equipment have the common feature that the working parts, such as the part of the piston rod outside the cylinder, are fully exposed to the surroundings so that they are likely to become dirty or to be damaged. It is more particularly in applications in dirt-laden atmospheres, as for instance in the neighborhood of machine tools that particles of dirt, turnings and the like, become deposited on the moving parts and this then leads to damage to the exposed running surfaces and seals of the respective receiving member. The respective devices then have to be frequently replaced.